A PathLike instance for Active p where p is also
PathLike, which simply lifts a pathlike thing to a constant
active value.

A Juxtaposable instance for Active a where a is also
Juxtaposable. An active value can be juxtaposed against
another by doing the juxtaposition pointwise over time. The
era of juxtapose v a1 a2 will be the same as the era of a2,
unless a2 is constant, in which case it will be the era of
a1. (Note that juxtapose v a1 a2 and liftA2 (juxtapose v)
a1 a2 therefore have different semantics: the second is an
active value whose era is the combination of the eras of a1
and a2).